Originally Posted by
terrymorse
Yes, Z5 is above 100% of FTP.
But here's the great part -- you can manually enter whatever FTP you want. Pick a small FTP, and now you're doing a bunch of Z5 without working very hard.
Yes, that's a big issue when using power. It's difficult to get it just right because different riders have different abilities. If I set my FTP at a level where I could actually ride at that level for a hour, it would be stupid low and I wouldn't get helpful workouts that actually did anything. FTP and lactate threshold should be at about the same power level, which is also about the same as the VT1/VT2 transition. So I set my FTP at a little below that transition point because it's easy to find during a normal ride or workout.
Thus I know perfectly well when I'm in Z5 because I'm panting. If I'm not panting, I'm somewhere below that zone. In my 60s, I could reliably hold lower Z5 for about 10 minutes before I blew up. That's not all out, obviously. Back then I could hold all out for about 45", now it's down to 30" and the power starts to drop. I can kick harder than that of course, but can't hold that peak. If I'm training hard, I'll get an hour or less in Z4 and maybe 20' in zone 5 - over a whole week's rides, working as hard as I can recover from.
Of course people are going to say, "but the definition of FTP . . .". So what. I get results which have stayed stable over the past couple of decades, meaning amount of time in Z4 and Z5 and IF have stayed at about what they should be for an averagely talented recreational rider.as my fitness has gone up and down.